An electric junction box installed in, e.g., an engine compartment of an automobile is provided with a connection processing component for a wire harness, an electric part of such a relay or fuse, or an electric component of such an electric control unit, which is therefore required to be kept away from water when traveling in the rain or washing the engine compartment with high-pressure. This requires the electric junction box to be configured waterproofed by letting the box main body accommodating such the above electric parts and a cover covering an upper opening of the box main body each have waterproof structures. The electric junction box thus serves as a waterproof box.
For a waterproof box, there are well-known a type of waterproof by filling a packing between a waterproof structure provided in the box main body and a waterproof structure provided in the cover (e.g., see PTL 1), and a type of waterproof by overlaying a waterproof structure of the cover on a waterproof structure of the box main body without a packing (e.g., see PTL 2).
With the type of waterproof using a packing, the packing between the waterproof structures is adapted to fill a clearance, which thus improves waterproof performance but poses a drawback of increase of parts count and cost incurred by the packing. Further, there is a drawback of not avoiding additional man-hour for filling of the packing. This has recently prompted a packing-less type waterproof.
With the packing-less-type waterproof, what is disclosed in the below PTL 2 is configured to be provided with a box main body with an upper opening and a cover covering the upper opening of the box main body. The waterproof box is designed to waterproof by overlaying waterproof structures to each other disposed at a seam portion of the box main body and the cover. Specifically, the waterproof structure of the box main body has a waterproof annular convex circumferentially arranged at a tip position of a side wall of the box main body, and that of the cover has a waterproof annular concave circumferentially arranged at a tip position of a side wall of the cover.
In the above-mentioned configuration and structure, the cover is arranged above the opening of the box main body, is then straightforwardly moved, and the waterproof structures are overlaid to each other, which thus makes the waterproof concave engage the waterproof convex. The box main body and the cover are also locked in a main body lock provided with the waterproof structure of the box main body by virtue of a U-shaped cover lock provided with the waterproof structure of the cover being latched, resulting in a locking state. The main body lock and the cover lock are arranged at least two positions of the sides (or back and forth) of the waterproof. The two positions are arranged separated from each other.